1. Field of the Invention
The present invention relates to a filter device, and in particular relates to a filter device utilized to filter a light.
2. Description of the Related Art
In FIG. 1, a conventional filter device 1 includes an outer steel pipe 2 for fixation, a first optical fiber aligner 3 disposed in one end of the outer steel pipe 2, and a second optical fiber aligner 4 disposed in the other end of the outer steel pipe 2. The outer steel pipe 2 is provided with a plurality of welding holes, and tin solders 6 applied at the welding holes. The ends of the outer steel pipe 2 are utilized for connecting the outer steel pipe 2 to the first and second optical fiber aligners 3 and 4.
The first optical fiber aligner 3 includes a glass outer tube 31 having an inner hole 32, an outer steel tube 33, an optical guide tube 34 adhered to one end of the inner hole 32 of the glass outer tube 31 by thermosetting glue 38, and a lens 36 provided with a graduated refractive rate. The outer steel tube 33 is jacketed outside of the glass outer tube 31. The optical guide tube 34 includes a slanted end surface 340e, a central hole and an optical fiber 37 disposed in the central hole. The lens 36 having a slanted end surface 360e is adhered to the other end of the inner hole 32 of the glass outer tube 31 by the thermosetting glue 38, and the slanted end surface 360e of the lens 36 is correspondingly spaced from the slanted end surface 340e of the optical guide tube 34.
The structure of the second optical fiber aligner 4 is similar to that of the first optical fiber aligner 3. The second optical fiber aligner 4 includes a glass outer tube 41 having an inner hole 42, an outer steel tube 43, an optical guide tube 44 adhered to one end of the inner hole 42 of the glass outer tube 41 by thermosetting glue 48, and a lens 46 provided with a graduated refractive rate.
The outer steel tube 43 is jacketed outside of the glass outer tube 41. The optical guide tube 44 includes a slanted end surface 440e, a central hole and an optical fiber 47 disposed in the central hole. The lens 46 having a slanted end surface 460e is adhered to the other end of the inner hole 42 of the glass outer tube 41 by the thermosetting glue 48, and the slanted end surface 460e of the lens 46 is correspondingly spaced from the slanted end surface 440e of the optical guide tube 44. The lens 36 of the first optical fiber aligner 3 is closer to the lens 46 of the second optical fiber aligner 4.
A filter 5 is disposed at the end of the lens 36 of the first optical fiber aligner 3 with UV glue 51. The light passing through the first optical fiber aligner 3 is filtered by the filter 5, and then the filtered light with particular wavelengths is collected and transmitted by the second optical fiber aligner 4.
Because the conventional filter device 1 comprises many components and is complicated, the optical guide tube 34, the optical guide tube 44, and the lenses 36 and 46 must be adhered to the glass outer tubes 31 and 41 by the thermosetting glues 38 and 48 when the first and second optical fiber aligners 3 and 4 are respectively assembled. The thermosetting glues 38 and 48 must be first dot-wised applied between the glass outer tubes 31 and 41 and the outer steel tubes 33 and 43 and then dried. Following, the first optical fiber aligner 3 can be adhered to the filter 5 when the assembly of the first optical fiber aligner 3 is completed, and then the outer steel pipe 2 is outwardly disposed on and welded to the first and second optical fiber aligners 3 and 4. However, the welding process sometimes causes damage to the applied thermosetting glues 38 and 48, and therefore the lifespan and reliability of the filter device 1 decreases. Furthermore, due to the long operational hours for the welding process, the cost of the filter device 1 is relatively increased.